[Andrew Blair]

Well, i'm not sure the butter would be any good, but I could be wrong. A cutting fluid does several things as I understand:

1. Keeps a bit cool, therefore keeping it from being tempered, etc. To do this, the fluid needs to stay intact and consistant, i.e. not burn at low temperatures, like butter does. Ever leave butter in a hot pan and come back 10 seconds later? Doesn't last too long.

2.Lubricates the two surfaces in contact to a degree. Just enough to allow cutting, but also help preserve the cutter. Butter might do this.

3. Clear chips. I think that a good fluid actually tries to move chips, keeping the cutter clear so it can cut without obstruction. Probably not.

4. Be fluid. Until you melt butter, it's very hard. Sounds like a good explanation to me.

The other problem is that if you didn't clean it all up, it'd rot after a while.

And then there's the saftey issue. I'd be worried that the 9th graders would constantly be trying to lick the endmill. Not good, if you know what I mean...

But, in a tapping situation, I had never thought of this. If I was in a pinch, I might do it, but it'd be an absolute last resort.